Water is one of the most important companions during a marathon. Calculating how much of it you need can be a challenge when you have to consider multiple factors like weather, sweat rate and rate of exertion. But maybe sometimes we forget the simplest factor – that it can be as simple as drinking when you are thirsty, writes Nandini Reddy.
Researchers around the world have spent hours determining how much water should be consumed based on a number of scientific factors and have always disregarded thirst as a factor. But many regular runners and sports physicians still swear that it is the thirst that should drive a runners’ water intake during a marathon. So regular runners now go with the rather simplistic philosophy for staying hydrated – dry mouth.
Understanding Hydration needs
Before we go on to simplify water intake let us consider what really happens to runners when they run without drinking any water. If a runner were to finish a marathon without taking a sip of water and running at his fastest pace (approximately 3min/km), it is likely he would be the winner and would have lost about 3 – 4 kilograms in weight from the water loss. But most race winners don’t win because they don’t drink any water but because they know how to space their water sips as their mouth dries up. They don’t go through litres of water to quench their thirst but take small sips through the duration of the race. You might notice that most don’t go through more than 1 – 1.5 litres. If you are wondering about dehydration then you need to remember that it doesn’t because the body is consistently getting small quantities of water.
An average recreational runner we see every day will always carry a bottle irrespective of the distance they are running. But a study published in the Journal of the International Society of Sports Nutrition in 2016, that studied the water consumption habits of Ethiopian runners noted that only modest amounts of fluids were consumed post the run and never before or during. The re-hydration process of the fluid lost during running should be done through the day and not at a single time when we gulp down water just after a race.
Don’t Drink Drink Drink
There is a school of thought that typically asks runners to drink as much water as they sweat out. But in reality the more water you drink you might be spending time running to the portable toilets than actually helping your body. Excess water can also cause sodium in your body to be heavily diluted resulting in a condition that has been seen in races of runners, known as Hyponatraemia. Marathons across the world have hardly reported deaths or illness due to thirst but there have been several cases of Hyponatraemia. Isotonic sports drinks also should be consumed with the same philosophy as water. Isotonic drinks over-consumption can also result in Hyponatraemia because the sodium they replenish will not help attenuate the drop in sodium levels due to dilution.
There is also an argument that depending on the weather dehydration can set in faster in certain places if fluids are not consumed. While temperature and humidity have a good role to play in how fast and how much we sweat, it should also be noted that water needs to be consumed but in minimal quantities, because the symptoms of dehydration and Hyponatraemia are quite similar and one might end up confusing them. In both cases, you will experience disorientation, fatigue, nausea and headaches. In that case, you should consider quitting your run instead of chugging down water because you just might make a simple condition worse.
Remember that hydration the right way is more important than meeting water capacity targets.